Vapor phase soldering can improve solder paste wetting and SIR results.

Vapor phase reflow effect on solder paste residue and surface insolation resistance

Vapor phase reflow is a mature process that solves the issue of preserving small discrete components on large thermal mass assemblies.  It has shown in this testing, and previously reported work to afford superior wetting to convection oven reflow.

The SIR data also indicates that vapor phase reflow, like nitrogen inertion in convection reflow, increases the SIR results of a no clean solder paste.